Pipettes have evolved from relatively simple straw-type structures to sophisticated electronic hand-held devices which exhibit a great degree of precision.
Typically, for a technician in a laboratory environment, pipetting may occupy only some, but as much as all of the technician's time during the course of employment. The work done by the technician requires great accuracy, and precision pipettes have made chemical assays accurate and reproducible. But, frequently this precision can come at the expense of the technician's physical constitution when the technician must perform repetitive tasks over protracted periods of time using cumbersome equipment.
Carpal Tunnel Syndrome is now a recognized malady that can be traced to the prolonged use of prior art pipettes. Factors found to have a deleterious effect on the physiology of the pipette user include excessive weight of the pipette, a contour which does not lend itself to easily grasping the pipette, requirements of unnatural motion of the digits of the hand manipulating the pipette, and asymmetry of the pipette device mandating deployment only by one hand, thereby giving the technician no opportunity to "load-shift" by switching hands.
The following prior art reflects the state of the art of which applicant is aware and is included herewith to discharge applicant's acknowledged duty to disclose relevant prior art. It is respectfully stipulated, however, that none of these references teach singly nor when considered in any conceivable combination teach the nexus of the instant invention as particularly set forth and claimed hereinafter.
______________________________________ PATENT NO. ISSUE DATE INVENTOR ______________________________________ U.S. PATENT DOCUMENTS 4,096,750 June 27, 1978 Sturm 4,154,108 May 15, 1979 Vollinger, et al. 4,197,735 April 15, 1980 Munzer, et al. 4,474,071 October 2, 1984 Marteau d'Autry 4,487,081 December 11, 1984 De Vaughn, et al. 4,517,850 May 21, 1985 Wiseman, et al. 4,567,780 February 4, 1986 Oppenlander, et al. 4,586,546 May 6, 1986 Mezei, et al. 4,6i6,5i4 October 14, 1986 Magnussen, Jr., et al. 4,6i7,0i6 October 14, 1986 Blomberg 4,671,123 June 9, 1987 Magnussen, Jr., et al. 4,821,586 April 18, 1989 Scordato, et al. 4,896,270 January 23, 1990 Kaimakis, et al. 4,905,526 March 6, 1990 Magnussen, Jr., et al. 4,967,604 November 6, 1990 Arpagaus, et al. 5,187,990 February 23, 1993 Magnussen, Jr., et al. 5,192,511 March 9, 1993 Roach 5,347,878 September 20, 1994 Suovaniemi 5,355,738 October 18, 1994 Heinonen 5,364,595 November 15, 1994 Smith 5,364,596 November 15, 1994 Magnussen, Jr., et al. 5,392,914 February 28, 1995 Lemiueux, et al. FOREIGN PATENT DOCUMENTS FR 2,071,052 September 17, 1971 Generale D'Automatisme DE 2,736,551 March 2, 1978 Oxford Labs, Inc. DE 2,651,333 May 11, 1978 Sarstedt EP 0,078,724 May 11, 1983 Marteau D'Autry EP 0 152 120 August 21, 1985 Rainin Instruments Co. EP 0 428 500 May 22, 1991 Rainin Instruments Co. OTHER PRIOR ART (Including Author, Title, Date, Pertinent Pages, Etc.) Rainin Instrument Company; Rainin Product Update; March 1996 issue; entire issue. *Fall/Winter Bio Consumer Review, 1996 issue, Powered by Katharine Glover, Ph. D., entire article (pages 12 through 14). ______________________________________
One common complaint involves the manner in which prior art pipettes address the hand of the user. A well designed pipette should be balanced so that it rests comfortably in the palm of the user with the majority of the weight being distributed along the length of the hand to minimize pressure spots. Another common observation involves the use of the thumb for effecting the pipette process. It is desired that a relatively small amount of thumb motion be required and that the thumb address the plunger assembly in a natural, biomechanically advantageous manner. Because pipettes frequently use disposable tips which are replaced after each use, it is also desirable to have a tip ejector which removes the old tip in a natural, biomechanically correct motion to further reduce technician operator fatigue.
The prior art listed above generally teach devices for fluid transfer that exemplify the above-discussed problems and catalog the prior art of which the applicant is aware. These references diverge starkly from the invention specifically distinguished hereinafter.